#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
ambari_jinja2.runtime
~~~~~~~~~~~~~~

Runtime helpers.

:copyright: (c) 2010 by the Jinja Team.
:license: BSD.
"""

import sys
from itertools import chain
from ambari_jinja2.nodes import EvalContext, _context_function_types
from ambari_jinja2.utils import (
  Markup,
  partial,
  soft_unicode,
  escape,
  missing,
  concat,
  internalcode,
  next,
  object_type_repr,
)
from ambari_jinja2.exceptions import (
  UndefinedError,
  TemplateRuntimeError,
  TemplateNotFound,
)


# these variables are exported to the template runtime
__all__ = [
  "LoopContext",
  "TemplateReference",
  "Macro",
  "Markup",
  "TemplateRuntimeError",
  "missing",
  "concat",
  "escape",
  "markup_join",
  "unicode_join",
  "to_string",
  "identity",
  "TemplateNotFound",
]

#: the name of the function that is used to convert something into
#: a string.  2to3 will adopt that automatically and the generated
#: code can take advantage of it.
to_string = str

#: the identity function.  Useful for certain things in the environment
identity = lambda x: x


def markup_join(seq):
  """Concatenation that escapes if necessary and converts to unicode."""
  buf = []
  iterator = map(soft_unicode, seq)
  for arg in iterator:
    buf.append(arg)
    if hasattr(arg, "__html__"):
      return Markup("").join(chain(buf, iterator))
  return concat(buf)


def unicode_join(seq):
  """Simple args to unicode conversion and concatenation."""
  return concat(map(str, seq))


def new_context(
  environment, template_name, blocks, vars=None, shared=None, globals=None, locals=None
):
  """Internal helper to for context creation."""
  if vars is None:
    vars = {}
  if shared:
    parent = vars
  else:
    parent = dict(globals or (), **vars)
  if locals:
    # if the parent is shared a copy should be created because
    # we don't want to modify the dict passed
    if shared:
      parent = dict(parent)
    for key, value in locals.items():
      if key[:2] == "l_" and value is not missing:
        parent[key[2:]] = value
  return Context(environment, parent, template_name, blocks)


class TemplateReference(object):
  """The `self` in templates."""

  def __init__(self, context):
    self.__context = context

  def __getitem__(self, name):
    blocks = self.__context.blocks[name]
    wrap = self.__context.eval_ctx.autoescape and Markup or (lambda x: x)
    return BlockReference(name, self.__context, blocks, 0)

  def __repr__(self):
    return f"<{self.__class__.__name__} {self.__context.name!r}>"


class Context(object):
  """The template context holds the variables of a template.  It stores the
  values passed to the template and also the names the template exports.
  Creating instances is neither supported nor useful as it's created
  automatically at various stages of the template evaluation and should not
  be created by hand.

  The context is immutable.  Modifications on :attr:`parent` **must not**
  happen and modifications on :attr:`vars` are allowed from generated
  template code only.  Template filters and global functions marked as
  :func:`contextfunction`\s get the active context passed as first argument
  and are allowed to access the context read-only.

  The template context supports read only dict operations (`get`,
  `keys`, `values`, `items`, `iterkeys`, `itervalues`, `iteritems`,
  `__getitem__`, `__contains__`).  Additionally there is a :meth:`resolve`
  method that doesn't fail with a `KeyError` but returns an
  :class:`Undefined` object for missing variables.
  """

  __slots__ = (
    "parent",
    "vars",
    "environment",
    "eval_ctx",
    "exported_vars",
    "name",
    "blocks",
    "__weakref__",
  )

  def __init__(self, environment, parent, name, blocks):
    self.parent = parent
    self.vars = {}
    self.environment = environment
    self.eval_ctx = EvalContext(self.environment, name)
    self.exported_vars = set()
    self.name = name

    # create the initial mapping of blocks.  Whenever template inheritance
    # takes place the runtime will update this mapping with the new blocks
    # from the template.
    self.blocks = dict((k, [v]) for k, v in blocks.items())

  def super(self, name, current):
    """Render a parent block."""
    try:
      blocks = self.blocks[name]
      index = blocks.index(current) + 1
      blocks[index]
    except LookupError:
      return self.environment.undefined(
        f"there is no parent block called {name!r}.", name="super"
      )
    return BlockReference(name, self, blocks, index)

  def get(self, key, default=None):
    """Returns an item from the template context, if it doesn't exist
    `default` is returned.
    """
    try:
      return self[key]
    except KeyError:
      return default

  def resolve(self, key):
    """Looks up a variable like `__getitem__` or `get` but returns an
    :class:`Undefined` object with the name of the name looked up.
    """
    if key in self.vars:
      return self.vars[key]
    if key in self.parent:
      return self.parent[key]
    return self.environment.undefined(name=key)

  def get_exported(self):
    """Get a new dict with the exported variables."""
    return dict((k, self.vars[k]) for k in self.exported_vars)

  def get_all(self):
    """Return a copy of the complete context as dict including the
    exported variables.
    """
    return dict(self.parent, **self.vars)

  @internalcode
  def call(__self, __obj, *args, **kwargs):
    """Call the callable with the arguments and keyword arguments
    provided but inject the active context or environment as first
    argument if the callable is a :func:`contextfunction` or
    :func:`environmentfunction`.
    """
    if __debug__:
      __traceback_hide__ = True
    if isinstance(__obj, _context_function_types):
      if getattr(__obj, "contextfunction", 0):
        args = (__self,) + args
      elif getattr(__obj, "evalcontextfunction", 0):
        args = (__self.eval_ctx,) + args
      elif getattr(__obj, "environmentfunction", 0):
        args = (__self.environment,) + args
    try:
      return __obj(*args, **kwargs)
    except StopIteration:
      return __self.environment.undefined(
        "value was undefined because " "a callable raised a " "StopIteration exception"
      )

  def derived(self, locals=None):
    """Internal helper function to create a derived context."""
    context = new_context(
      self.environment, self.name, {}, self.parent, True, None, locals
    )
    context.eval_ctx = self.eval_ctx
    context.blocks.update((k, list(v)) for k, v in self.blocks.items())
    return context

  def _all(meth):
    proxy = lambda self: getattr(self.get_all(), meth)()
    proxy.__doc__ = getattr(dict, meth).__doc__
    proxy.__name__ = meth
    return proxy

  keys = _all("keys")
  values = _all("values")
  items = _all("items")

  # not available on python 3
  if hasattr(dict, "iterkeys"):
    iterkeys = _all("iterkeys")
    itervalues = _all("itervalues")
    iteritems = _all("iteritems")
  del _all

  def __contains__(self, name):
    return name in self.vars or name in self.parent

  def __getitem__(self, key):
    """Lookup a variable or raise `KeyError` if the variable is
    undefined.
    """
    item = self.resolve(key)
    if isinstance(item, Undefined):
      raise KeyError(key)
    return item

  def __repr__(self):
    return f"<{self.__class__.__name__} {repr(self.get_all())} of {self.name!r}>"


# register the context as mapping if possible
try:
  try:
    from collections.abc import Mapping
  except ImportError:
    from collections import Mapping

  Mapping.register(Context)
except ImportError:
  pass


class BlockReference(object):
  """One block on a template reference."""

  def __init__(self, name, context, stack, depth):
    self.name = name
    self._context = context
    self._stack = stack
    self._depth = depth

  @property
  def super(self):
    """Super the block."""
    if self._depth + 1 >= len(self._stack):
      return self._context.environment.undefined(
        f"there is no parent block called {self.name!r}.", name="super"
      )
    return BlockReference(self.name, self._context, self._stack, self._depth + 1)

  @internalcode
  def __call__(self):
    rv = concat(self._stack[self._depth](self._context))
    if self._context.eval_ctx.autoescape:
      rv = Markup(rv)
    return rv


class LoopContext(object):
  """A loop context for dynamic iteration."""

  def __init__(self, iterable, recurse=None):
    self._iterator = iter(iterable)
    self._recurse = recurse
    self.index0 = -1

    # try to get the length of the iterable early.  This must be done
    # here because there are some broken iterators around where there
    # __len__ is the number of iterations left (i'm looking at your
    # listreverseiterator!).
    try:
      self._length = len(iterable)
    except (TypeError, AttributeError):
      self._length = None

  def cycle(self, *args):
    """Cycles among the arguments with the current loop index."""
    if not args:
      raise TypeError("no items for cycling given")
    return args[self.index0 % len(args)]

  first = property(lambda x: x.index0 == 0)
  last = property(lambda x: x.index0 + 1 == x.length)
  index = property(lambda x: x.index0 + 1)
  revindex = property(lambda x: x.length - x.index0)
  revindex0 = property(lambda x: x.length - x.index)

  def __len__(self):
    return self.length

  def __iter__(self):
    return LoopContextIterator(self)

  @internalcode
  def loop(self, iterable):
    if self._recurse is None:
      raise TypeError(
        "Tried to call non recursive loop.  Maybe you "
        "forgot the 'recursive' modifier."
      )
    return self._recurse(iterable, self._recurse)

  # a nifty trick to enhance the error message if someone tried to call
  # the the loop without or with too many arguments.
  __call__ = loop
  del loop

  @property
  def length(self):
    if self._length is None:
      # if was not possible to get the length of the iterator when
      # the loop context was created (ie: iterating over a generator)
      # we have to convert the iterable into a sequence and use the
      # length of that.
      iterable = tuple(self._iterator)
      self._iterator = iter(iterable)
      self._length = len(iterable) + self.index0 + 1
    return self._length

  def __repr__(self):
    return f"<{self.__class__.__name__} {self.index!r}/{self.length!r}>"


class LoopContextIterator(object):
  """The iterator for a loop context."""

  __slots__ = ("context",)

  def __init__(self, context):
    self.context = context

  def __iter__(self):
    return self

  def __next__(self):
    ctx = self.context
    ctx.index0 += 1
    return next(ctx._iterator), ctx


class Macro(object):
  """Wraps a macro function."""

  def __init__(
    self,
    environment,
    func,
    name,
    arguments,
    defaults,
    catch_kwargs,
    catch_varargs,
    caller,
  ):
    self._environment = environment
    self._func = func
    self._argument_count = len(arguments)
    self.name = name
    self.arguments = arguments
    self.defaults = defaults
    self.catch_kwargs = catch_kwargs
    self.catch_varargs = catch_varargs
    self.caller = caller

  @internalcode
  def __call__(self, *args, **kwargs):
    # try to consume the positional arguments
    arguments = list(args[: self._argument_count])
    off = len(arguments)

    # if the number of arguments consumed is not the number of
    # arguments expected we start filling in keyword arguments
    # and defaults.
    if off != self._argument_count:
      for idx, name in enumerate(self.arguments[len(arguments) :]):
        try:
          value = kwargs.pop(name)
        except KeyError:
          try:
            value = self.defaults[idx - self._argument_count + off]
          except IndexError:
            value = self._environment.undefined(
              f"parameter {name!r} was not provided", name=name
            )
        arguments.append(value)

    # it's important that the order of these arguments does not change
    # if not also changed in the compiler's `function_scoping` method.
    # the order is caller, keyword arguments, positional arguments!
    if self.caller:
      caller = kwargs.pop("caller", None)
      if caller is None:
        caller = self._environment.undefined("No caller defined", name="caller")
      arguments.append(caller)
    if self.catch_kwargs:
      arguments.append(kwargs)
    elif kwargs:
      raise TypeError(
        f"macro {self.name!r} takes no keyword argument {next(iter(kwargs))!r}"
      )
    if self.catch_varargs:
      arguments.append(args[self._argument_count :])
    elif len(args) > self._argument_count:
      raise TypeError(
        f"macro {self.name!r} takes not more than {len(self.arguments)} argument(s)"
      )
    return self._func(*arguments)

  def __repr__(self):
    return "<%s %s>" % (
      self.__class__.__name__,
      self.name is None and "anonymous" or repr(self.name),
    )


class Undefined(object):
  """The default undefined type.  This undefined type can be printed and
  iterated over, but every other access will raise an :exc:`UndefinedError`:

  >>> foo = Undefined(name='foo')
  >>> str(foo)
  ''
  >>> not foo
  True
  >>> foo + 42
  Traceback (most recent call last):
    ...
  UndefinedError: 'foo' is undefined
  """

  __slots__ = (
    "_undefined_hint",
    "_undefined_obj",
    "_undefined_name",
    "_undefined_exception",
  )

  def __init__(self, hint=None, obj=missing, name=None, exc=UndefinedError):
    self._undefined_hint = hint
    self._undefined_obj = obj
    self._undefined_name = name
    self._undefined_exception = exc

  @internalcode
  def _fail_with_undefined_error(self, *args, **kwargs):
    """Regular callback function for undefined objects that raises an
    `UndefinedError` on call.
    """
    if self._undefined_hint is None:
      if self._undefined_obj is missing:
        hint = f"{self._undefined_name!r} is undefined"
      elif not isinstance(self._undefined_name, str):
        hint = "%s has no element %r" % (
          object_type_repr(self._undefined_obj),
          self._undefined_name,
        )
      else:
        hint = "%r has no attribute %r" % (
          object_type_repr(self._undefined_obj),
          self._undefined_name,
        )
    else:
      hint = self._undefined_hint
    raise self._undefined_exception(hint)

  __add__ = __radd__ = __mul__ = __rmul__ = __div__ = __rdiv__ = __truediv__ = (
    __rtruediv__
  ) = __floordiv__ = __rfloordiv__ = __mod__ = __rmod__ = __pos__ = __neg__ = (
    __call__
  ) = __getattr__ = __getitem__ = __lt__ = __le__ = __gt__ = __ge__ = __int__ = (
    __float__
  ) = __complex__ = __pow__ = __rpow__ = _fail_with_undefined_error

  def __str__(self):
    return ""

  def __len__(self):
    return 0

  def __iter__(self):
    if 0:
      yield None

  def __bool__(self):
    return False

  def __repr__(self):
    return "Undefined"


class DebugUndefined(Undefined):
  """An undefined that returns the debug info when printed.

  >>> foo = DebugUndefined(name='foo')
  >>> str(foo)
  '{{ foo }}'
  >>> not foo
  True
  >>> foo + 42
  Traceback (most recent call last):
    ...
  UndefinedError: 'foo' is undefined
  """

  __slots__ = ()

  def __unicode__(self):
    if self._undefined_hint is None:
      if self._undefined_obj is missing:
        return "{{ %s }}" % self._undefined_name
      return "{{ no such element: %s[%r] }}" % (
        object_type_repr(self._undefined_obj),
        self._undefined_name,
      )
    return "{{ undefined value printed: %s }}" % self._undefined_hint


class StrictUndefined(Undefined):
  """An undefined that barks on print and iteration as well as boolean
  tests and all kinds of comparisons.  In other words: you can do nothing
  with it except checking if it's defined using the `defined` test.

  >>> foo = StrictUndefined(name='foo')
  >>> str(foo)
  Traceback (most recent call last):
    ...
  UndefinedError: 'foo' is undefined
  >>> not foo
  Traceback (most recent call last):
    ...
  UndefinedError: 'foo' is undefined
  >>> foo + 42
  Traceback (most recent call last):
    ...
  UndefinedError: 'foo' is undefined
  """

  __slots__ = ()
  __iter__ = __unicode__ = __str__ = __len__ = __nonzero__ = __eq__ = __ne__ = (
    __bool__
  ) = Undefined._fail_with_undefined_error


# remove remaining slots attributes, after the metaclass did the magic they
# are unneeded and irritating as they contain wrong data for the subclasses.
del Undefined.__slots__, DebugUndefined.__slots__, StrictUndefined.__slots__
